Worldwide data centre hardware spending is projected to reach $98.9bn in 2011, up 12.7% from 2010 spending of $87.8bn, according to IT research firm Gartner.

Gartner also forecasted that data centre hardware spending, which includes servers, storage and enterprise data centre networking equipment, will total to $106.4bn in 2012, and surpass $126.2bn in 2015.

Gartner research director Jon Hardcastle said growth in emerging regions – particularly Brazil, Russia, India and China (the BRIC countries) – is balanced by continued weakness relative to pre-downturn levels in Japan and Western Europe.

"Storage is the main driver for growth. Although only a quarter of data center hardware spending is on storage, almost half of the growth in spending will be from the storage market," Hardcastle said.

The very largest size category of data centres (more than 500 racks of equipment) will increase its share of spending from 20% in 2010 to 26% in 2015, driven by the cloud and the shift from internal data centre provision to external.

In 2010, 2% of data centres contained 52% of total data centre floorspace and accounted for 63% of data centre hardware spending.

In 2015, 2% of data centres will contain 60% of data centre floorspace and account for 71% of data centre hardware spending, the report said.

"Traditional in-house enterprise data centres are under attack from three sides. Firstly, virtualisation technologies are helping companies to utilise their infrastructure more effectively, inhibiting overall system growth. Secondly, data centres are getting more efficient, leading to higher system deployment densities and inhibiting demand for floor space. Thirdly, the move to consolidated third-party data centres is reducing the overall number of midsize data centres," Hardcastle said.

"Meanwhile, the largest data center class is, of course, benefitting from the rise of cloud computing."